Clinical value of an amplified electrophoretic determination of enolase isoenzymes in small cell lung carcinoma patients.

Neurone specific enolase (NSE); alpha gamma and gamma gamma isoenzymes of the glycolytic enzyme enolase, is found in considerable quantity in serum of patients with small cell lung cancer (SCLC). The spectrophotometric measurement of serum enolase activity, plus the electrophoretic separation of isoenzymes (alpha alpha, alpha gamma and gamma gamma) using an amplification reaction constitute a simple method, the application of which has not yet been demonstrated. In patients, serum values of higher than 25 U/l of total enolase activity, with more than 10% NSE, were considered to be positive. Seventy patients diagnosed as SCLC were classified before treatment as having either limited (LD) or extensive (ED) disease, and after chemotherapy as being in complete (CR) or partial remission (PR), stable state (SS) or in relapse (R). The levels of enolase activity and NSE (M +/- SE) in these patients (enolase: 67 +/- 7 U/l, NSE 27 +/- 2%) were different from those in a control group of 19 patients with non-small cell lung cancer (enolase: 29 +/- 2 U/l, NSE: 7 +/- 1%) (p less than 0.001) at the time of diagnosis. Mean enolase and NSE levels in patients with SCLC were seen to differ significantly according to the clinical stage. The results of those patients with ED differed from those of patients with LD (p less than 0.001). The results of the group of patients that achieved remission differed from that of patients during relapse (p less than 0.0001). Serial measurements demonstrated a good correlation between enolase and NSE serum levels and the progression of the disease. The usefulness of this method in the early assessment of treatment was also demonstrated. The clinical usefulness of the dosage of NSE with that of two other tumour markers CKBB and mitochondrial CK was compared.